The present invention relates generally to improvements in illumination devices and relates, more particularly, to an improved electrical lighting fixture of the universally angularly adjustable type.
Conventional electrical lighting fixtures, of the focussed light type commonly used in illuminating displays or specifically delineated areas thereof, are generally universally angularly adjustable. In general, these fixtures have a stem in the form of a tubular shank which not only supports the lamp assembly, but normally provides a conduit through which electrical wires pass from a track to a bulb socket. One end of the support stem is normally connected to the lamp base through a coupling which permits relative rotation therebetween, whereby the lamp fixture may be aimed as required. If the lamp fixture is to be a so-called "track-light" type of fixture, the other end of the support stem is normally fitted with an appropriate support and electrical interconnect means, as is required by the particular track lighting structure and the weight of the lamp fixture.
Focussed light type universally adjustable lamp fixtures, whether permanently affixed to the ceiling or wall or of the track-light type, have at least two different types of constructions depending on the object to be illuminated. If the lamp is to be used for wall lighting for example, a lamp fixture using an obliquely cut shield collar construction is normally employed. If a tight spot-light type of illumination is required, such as to illuminate a sculpture or other item on display, a lamp fixture with a shield collar formed as a complete cylinder, to collimate the light is normally employed. Thus, different lamp fixtures were required for different uses.
The lens normally employed on spot-light lamp fixtures is formed with generally parallel defraction grooves to produce a required light pattern. When the lamp fixture is rotated about the stem to aim it or adjust it for a particular area to be illuminated, it is often necessary to rotate the lens to align the parallel grooves with respect to the area being lit, to obtain the desired light pattern. Normally this is done after the fixture has been aimed, by having someone press his fingers gently against the lens and rotate it until the desired light pattern is attained. If the lamp has been turned on for any appreciable time the lens becomes hot and there is potential for injury to the person rotating the lens.
It is therefore an object of the present invention to provide a universally adjustable lamp fixture which may be used in either a tight spot - or a broader flood-light mode by interchanging an easily removed light shield.
It is a related object to provide a universally adjustable lamp fixture which can quickly and easily be aimed to produce a desired light pattern.
It is a further object of the invention to provide a universally adjustable lamp fixture whereby, after the lamp has been aimed, the lens can be adjusted with a minimum of danger of burning the hands to the person doing the adjustment, by providing an adjustment means avoiding the need for direct contact between the hand of the person doing the adjustment and the potentially hot lens.